Circular-disk fan.



H. F. HAGEN.

CRCULAR DISK FAN.

APPLlcAIInM HLED MAY 5, Isla.

` patented July 10,1917.

UNTTED HTATEH PATENT HFFTQUE.

HAROLD F. I-IGEN, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO GREEN FUEL ECONOMIZER COMPANY, A CORPORATION OI NEW YORK.

CIRCULAR-:DISK FAN.

Application sied May 5, 1913.

To all whom t may concern.'

Be it known that I, HAROLD F. HAGEN, a citizen of the United States, residing at Jersey City, county of Hudson, and State of New Jersey, have invented certain new and useful improvements in Circular-Disk Fans, of which the following is a full, clear, and exact description.

The invention which constitutes the subject-matter of this application relates to -improvements in disk fans.

1n the conventional type of disk fan a number of straight blades, usually from siX to twelve, supported from a hub and reinforced by radial or substantially radial spokes or braces, forms the impeller. The angle formed by the intersection of the plane of the blade with the axis of rotation is necessarily a constant. This is a disadvantageous condition as it results ina greater amount of work being done near the tips of the blades and very little work being done at the smaller radii. This is a well recognized phenomenon and accounts for the blowing back through the center that is inevitable when this type of fan operates against even a small pressure. In addition the constructions are weak and make impracticable the direct connection of these Yfans to standard motors or steam turbines.

With the propeller type of fan having substantially helical blades the action of the air is of course greatly improved but, the present constructions are inadequate to allow the operation of large fans of this type at high speeds, the weakest part of the blade coming at the center, where the centrifugal stresses are the greatest.

The object of my invention consists in providing means for overcoming these ditIiculties. Other objects and advantages of the invention will appear from the detailed description below, taken in connection with the accompanying drawings, in which- Figure 1 is a front view of a disk fan provided with my improvements thereon.

Fig. 2 is a cross section of the same on line 2 2.

Fig. 3 is a cross section of the same on line 3-3.

Fig. 4 illustrates a modified form of the invention.

Referring in detail to the construction shown in Figs. 1 and 2, the reference nueral 10 designates the hub to which the sec- Speccation of Letters Patent.

)Patented July 10, 1917'.

serial No. 765,472.

tions of the blades are directly connected as `shown. Each of the blades is divided up into sections 11, 12 and 13. Sections 11, 12 and 13 each constitute in turn a Zone separated from each other by means of the concentric hoops or rings 14 which are preferably made of sheet steel. The blade sections are preferably riveted to the hoops or rings by means of angle irons 15 or by bending the edge of the blade as shown at 16. This provides a strong and durable construction, as it braces the blades to each other in a manner somewhat similar to the method of building structural columns where the channels are spaced apart to increase the radius of gyration. The number of these hoops or rings of course depends on the size of the fan, and the speed at which it is to operate, four being ample in most cases. @ne of the important advantages resulting from this method of bracing the blades is that it does not interfere with the free fiow of the air through the fan, nor does it cause the whirling disturbance which radial spokes set up. vFurthermore, if sectional blades be used, the pitch of each of said blade sections may be decreased in each succeeding Zone, as the radius becomes greater, thereby approximating the action of a costly blade pressed into substantially helical form. Another important feature of my invention lies in the fact that the inner blade sections may be of heavy metal and the outer ones of light metal, giving a smaller centrifugal stress and a greater strength to withstand that stress.

1n Fig. 4 I illustrate a modified form which, to all intents and purposes, accomplishes the same result of the invention. Instead of employing continuousrings or hoops, I provide sectors 17, 18, 19, and 20, 21, 22. As shown, each of these sectors connects two blades. Sectors. 17, 18 and 19 connect respectively blades a Z2, c (Z, and c f, whereas sectors 20, 21 and 22 connect respectively blades 7) c, d e, and 7" g. By this arrangement it will be readily apparent that the construction is such as to give an addi.- tional bracing.

fith formed blades, the advantages of my invention are even more pronounced, as the blade shape for each section may be designed independently as the hoops or rings e'lfectually prevent a whirling from one section to another, and to those skilled in this art it will be readily seen how this sectional independence may be utilized to secure a better eliiciency and a greater strength. Not only may the sections of the blades be independently designed, but it is equally obvious that an increased number of the inner blade sections may be used which secures a greater uniformity of pressure and air direction across the discharge area. And, as Will be apparent from the construction shown in Fig. 1, the inner sections may be made longer axially, thereby permitting the use of a greater subtended blade angle Without altering the correct delivery conditions, and giving consequently a greater length of blade in Contact with the hub. In an axial flow fan the blade angle may be regarded as substantially helical in its mostadvantageous form. A'helix has a pitch which is thel distance the helixA moves forward in one completerevolution. n one quarter of a revolutiomfor example, the helix Will move forwardone-fourth vof the pitch and the angle through Which the helix has traveled is called the subtended angle.

From the above description, taken in connection With the accompanying drawings, it will at'once be apparent that the invention is not strictly limited in its use to fans and it will 'appear obvious to any one skilled in the art that the invention is capable of use in any axial flow Wheel or impeller. It is also apparent that I do not restrict myself to the exact construction shown as changes maybe made in point of detail and other embodiments resorted to With- 'airis in a direction substantially parallel to the axis of rotation, an impeller comprising the combination of two series of elements' rigidly secured to eachother to form a plurality of concentric zones, one of said elements consisting of blades and the other consisting of hoops, the axial Width of Which increases with a decreasing radius thereby securing greater strength for high speeds, and one of said series being made sectional and the other continuous, substantially as described.

3. In a fan through which the flow of air is in a direction substantially parallel to the axis of rotation, an limpeller 'comprising Zones of blade sectionsin which the pitch of the blade sections in each zone is decreased as the radius becomes greater.

el. In a fan through which the flow of air is in a direction substantially parallel to the axis of rotation, an impelle-r comprising zones of blade sections in which the'axial length of the sections in each zone is decreased as the radius increases :Whereb'y' a greater subtended bladefangle is secured on the inner section.

5. In a fan 'of the dislr type, theV combination Vof hoops or rings 'and plane blades Vdivided into sections by said rings or hoops.

said blade sections rigidly secured toY Said rings or hoops and set at dierent angles Y to the axis of rotation so'as to increase the pitch of the inner sections, thereby tending to equalize the Work done in each section.

6. ln fan through Which the flowA of air is in a direction substantially parallel to the axis of rotation, 'an impeller formed by the combination of a'plurality of hoops or rings with blades in sections fastened thereto, said blade sections so variously formed as to lit betweenadjacent hoopsand to have an increased pitch in the inner sections.

7. A fan through Which the floyvfofuiir isin a direction substantially parallel to the axis of rotation, Vcomprisingblades in combination with means Efor bracing the said blades and fastening thesame to each other substantially concentric With the axis of rotation at a radius or radii between the hub radius'and the radius of the blade tips, substantially `as described.

In testimony whereof I aflix my signa? ture in the presence of two subscribing witnesses.

HAROLD F. HAGEN Witnesses: 7

THOMAS JJBYRNE, Wir. BOHLEBER.

Copies f-this patent may be obtained for ve cents each, by `addressing the Commissioner of'Pat'en'ts, 'Wasl1ing'ton,` D.- C. 

